The purpose of this research is to investigate how nucleic acids function by studying their dynamic properties. Included are projects on equilibria and kinetics of nucleosome folding using the temperature-jump method and transient electric dichroism. Also, the kinetics of binding and unwinding of closed circular DNA under superhelical stress will be examined. In addition, temperature-jump and high resolution NMR measurements will be combined to investigate the effect of ribosomal proteins on the conformation and dynamic properties of ribosomal RNAs. Studies of crosslinking of 5S RNA by psoralen are also in progress.